Questions tagged [periodic-trends]
Trends which are observed in the properties of elements as you move along the periodic table in a given direction.
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Effective nuclear charge increases along period despite increasing number of electrons
I learned that when an increasing number of electrons are present in the orbitals, then nuclear force decreases as it needs to hold more electrons.
Given this, why does the effective nuclear charge ...
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Why does chlorine have a higher electron affinity value than fluorine? [duplicate]
Why does chlorine have a higher electron affinity value than fluorine? Since this periodic property tends from the bottom up (in the group), the logic would be that the fluorine is the element with ...
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Atomic radius decreasing across a Periodic Table row - does the RPD of an orbital change depending of the element considered?
I have a concern regarding the RPD of an orbital. Does the RPD of an orbital depend on the $Z$ (i.e. on the element under consideration) ? Especially, can the RPD of an orbital "shrink" to ...
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Why does the 1st ionisation energy decrease from the 9th period to the 10th period
I’m currently looking at the ionisation energy chart within my chemistry textbook and while I know that there are not really meaningful periodic trends within transition metals, generally the ...
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Are Fajans rules relevant to melting and boiling points of alkali metal hydrides?
Among LiH, NaH, KH, RbH, CsH the one with the highest melting point is LiH, and it keeps on decreasing till CsH. The reason for this in my textbook is that the size of cations keeps on increasing down ...
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I was told that Lithium and group 2 bicarbonates does not decompose on heating.Group 1 bicarbonates does decompose except lithium
But in some sources it was explained that stability of group 1 bicarbonates increases down the group.If it is true then how does lithium bicarbonate does not decompose ?.Can anyone please tell me ...
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Upon what does the half life of a nuclide depend on? [duplicate]
Nuclide half-lives seem to be apparently random, except for the fact that heavier elements are typically radioactive and lighter ones stable. Is there any factor that can predict the half life of a ...
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Why aren't other elements with valence 6s electrons liquid like mercury?
I found out that mercury's 6s electrons undergo relativistic effects that make their pull to the nucleus greater, which makes it so that they can't bond with other atoms of mercury to form a solid. ...
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Why is there anomalous trend in third ionization energy for Pr-Pm and Dy-Er?
It is not hard to observe the anomalously flat regions at Pr-Pm and Dy-Er in the trend of IE3 of lanthanides:, each described as the "first quarter" and "third quarter". Why is ...
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Can the relative reactivity of metals be explained by ionization energy and/or electronegativity?
I'm a 9th grade physical science teacher, and we're currently learning periodic trends. This is the first chemistry my students have learned. One of our labs for this unit has to do with the relative ...
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How would you explain the general trend in melting point between Group 1 and Group 2 chlorides?
This question is based off of the attached chart. I notice how there's a general increase in melting point down group 2 chlorides and a general decrease (except for Lithium) down the group 1 chlorides....
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Ionic radii of cations and anions
My textbook mentions that across a period from left to right, the ionic radius of atoms decreases. I'm a bit puzzled because negative ions in the same period have an extra shell. I get the part about ...
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Does Cu+ have a greater ionic radius than Sr2+?
Although Strontium is in group 2, reducing the number of electrons as it becomes ionized makes it group 18, period 4 in terms of electrons. Therefore, ionized Strontium (Sr2+) is in the same period as ...
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Why aren't lanthanum, praseodymium, osmium, and mercury not on the same energy level?
The following question is from "The Official Guide to the HiSET Exam, Second Edition 2nd Edition", published by McGraw Hill, 2nd edition (March 25, 2016).2016 text, p. 75 (ISBN10: 1259640795)...
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Queries regarding Lanthanoid Contraction
Consider these two statements regarding lanthanoid contraction and their explanation as understood by me.
Lanthanoid contraction is the greater than expected decrease in the atomic radii of the ...
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Are periods the horizontal numbers on the periodic table and groups the vertical numbers?
I am writing this post so that I can ensure for my upcoming SUC3U0 (Chemistry, Grade 11) course test of nomenclature is correct. It's a Review of my Grade 10 General Science Course.
My teacher stated ...
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Do the paired electrons of subshells' degenerate orbitals contribute to the total exchange energy?
For instance, in d7, there are 5 electrons with the same spin, and 2 electron with the opposite spin, meaning that there are only 3 unpaired electrons. So, which of these would be correct?
(i) Total ...
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Some advice on inorganic textbook [duplicate]
I'd like to have some advice on Inorganic textbooks.
I've already consulted some books (Kettle, Drago, Keiter, Cotton) and they are all very useful, but now I'm searching for a textbook which focuses ...
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Why does Cr have higher melting point in the 4 period among the transition metal? [duplicate]
There is a lot of answer stating that the low enthalpy of atomisation in Cr is due to the reason of partially filled d orbital, thus having extra stability. This makes the orbital more attracted ...
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Why is there a non-uniformity in even the reasons that explain exceptions in the trends in chemistry? [closed]
I have been studying the periodic table and several properties of atoms like the Ionization Energy, Atomic Radii, Electron gain enthalpy, Electronegativity etc.
Now, each property has somewhat of a &...
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Please explain the order of Lewis acidic strength in trichlorides of boron group
The order of decreasing Lewis acid character as per online sources is as follows:
BCl3 > AlCl3 > GaCl3 > InCl3
Reason cited is: As we move down the group, the size of atom increases, and as a ...
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Comparison of atomic radii of boron and beryllium
Let me write down a couple of facts and this will be easier for you to know the essence of the question.
Radius of boron is smaller than beryllium.
Ionization energy of boron is smaller than ...
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Order of Second Ionisation Potential of C, N, O and F
Here's what I believe:
The electronic configurations of the elements after losing 1 electron are:
N+ -> 1s2 2s2 2p2
O+ -> 1s2 2s2 2p3
F+ -> 1s2 2s2 2p4
So, on losing 1 e- more, the value of ...
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Trend in formation enthalpy of metal fluorides
Please see below for the data I am referring to. I don't really understand why the trend in Cr ceases and reverses.
I think I understand what the logic for WFn is - while the cost of forming Mn+ ...
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Why do the successive ionisation energies of Ni and Pt diverge?
The data I am referring to is below on the graph. The explanation I have found is that the 5d orbital of Pt is more diffuse than the 3d orbital of Ni, so is less sensitive to the increases in Zeff as ...
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Why is CrO3 an oxidising agent, but WO3 is not?
So apparently CrO3 can be used as an oxidising agent, but WO3 can not. I saw this on an assignment question which I will include below:
I think the reason why W6+ is 6-coordinate and Cr6+ is 4-...
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Why ionic radius increases with negative charge?
Here's my understanding:
An ion with a negative charge has gained electrons. Hence the negative charge.
With a greater negative charge, there should be more attraction towards the positive charge.
As ...
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How did Mendeleev improve on the Newland's table?
I understand that John Newland’s law of octaves was ridiculed by the scientific community as his table failed to work past calcium. I'm trying to understand how Mendeleev’s table improved on this.
On ...
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Is the periodic table ordered by bonded atoms and does that change the electron configurations and ordering? [closed]
In my book (Mortimer, The Basic Knowledge of Chemistry) the electron structure of the elements is introduced, there the relative energies of the atomic orbitals are shown:
1s < 2s < 2p < 3s &...
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Lower melting points of zinc, cadmium and mercury
I am aware of the fact that d-block elements like zinc, cadmium and mercury have lower melting points than other d-block elements. Also I am aware that these three metals have a fully filled d shell.
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